American Board of Ophthalmology (ABO) Practice Exam 2025 – The Complete All-in-One Guide to Exam Success

Frame PD, or Frame Pupillary Distance, refers to the measurement of the distance between the geometric center of the right lens to the geometric center of the left lens within a pair of eyeglass frames. This measurement is crucial in optical fittings because it helps ensure that the lenses are properly positioned in front of the wearer's pupils, which is essential for optimal vision correction and comfort.

In the context of the question, the correct response accurately represents this specific measurement. Frame PD is critical when ordering lenses so that the optical centers of the lenses align with the wearer's pupils, ensuring that there is no distortion or blurring in the visual experience. Proper alignment minimizes the risk of eyestrain and maximizes visual clarity, particularly for individuals with strong prescriptions.

The other options, while related to different aspects of frame fitting, do not pertain directly to the Frame PD measurement. The distance from the bridge to the pupils may be an important measurement for fitting frames to the facial anatomy, but it does not define the spacing between the lens centers. The distance between the temples of the frame pertains to how the frame sits on the head but is not related to lens alignment. The total width of the frame gives a sense of overall size but also does not provide information about